In this paper, the fault contact pairs with viscoelastic mechanical parameters were established by using the finite element method. Through the comparative analysis method, factors affecting the tectonic stress field and the distribution state of the echelon fault were analyzed by changing the geometric spacing and viscosity coefficient of the fault. The stress drop and stress-strain relationship caused by earthquake during the instability process of the echelon fault were simulated, as well as the angle relationship among the first, second, and third principal stresses and fault.